YY2 in Mouse Preimplantation Embryos and in Embryonic Stem Cells

Area of Science:

• Developmental Biology
• Stem Cell Biology
• Epigenetics

Background:

• Yin Yang 2 (YY2) is a mammalian transcription factor with homology to YY1 and REX1/ZFP42.
• Known roles of YY1 and REX1 include gene regulation and X chromosome inactivation.
• The function of YY2, particularly during early development and in stem cells, is poorly understood.

Purpose of the Study:

• To investigate the expression pattern of YY2 during mouse preimplantation development.
• To elucidate the role of YY2 in the maintenance of mouse embryonic stem cells (mESC).
• To understand the mechanistic contribution of YY2 to mESC maintenance.

Main Methods:

• RT-PCR and polyclonal serum staining to detect YY2 expression in mouse embryos and mESC.
• Experimental manipulation of Yy2 levels in mESC using shRNA.
• Analysis of pluripotency markers (Sox2, Oct4, Nanog, Esrrb) and Zscan4 expression.
• Assessment of transposable element (TE) expression (IAP, MERVL).

Main Results:

• YY2 is expressed during mouse preimplantation development but is not essential for development until the blastocyst stage.
• Attenuation of Yy2 levels in mESC led to a decreased number of undifferentiated colonies.
• Yy2-depleted mESC showed increased Zscan4 expression but no significant changes in other pluripotency markers or TE expression.
• Contrary to previous reports, mESC propagation was possible with attenuated Yy2 levels.

Conclusions:

• YY2 is expressed during mouse preimplantation development.
• YY2 plays a role in the maintenance of mouse embryonic stem cells.
• YY2's function in mESC maintenance is linked to Zscan4 regulation, distinct from its roles in early development.